How 2 Colonels and a National Geographic Map Divided Korea

On the evening of August 10, 1945 two colonels convened in an office in the Pentagon to consider an extraordinary assignment. Imperial Japan was then only days away from surrender, and the fate of its subjugated Korean colony was in question. If the State Department did not clarify who would administrate which parts of Korea, then the entire peninsula would fall under the control of advancing Soviet troops.

But where should the dividing line be drawn?

Chris “Tick” Bonesteel and Dean Rusk were not lightweights by any means. Both were Rhodes Scholars, and Rusk would later serve as Secretary of State under presidents Kennedy and Johnson. But neither knew much about Korea.

“Bonesteel and I retired to an adjacent room late at night and studied intently a map of the Korean peninsula. Working in haste and under great pressure, we had a formidable task: to pick a zone for the American occupation. Neither Tic nor I was a Korea expert, but it seemed to us that Seoul, the capital, should be in the American sector.”

Using a National Geographic map of “Asia and Adjacent Areas” that lacked provincial borders, the two mid-ranking officers struggled to find a “convenient” boundary—so they settled upon a line at the thirty-eighth parallel north latitude. Rusk conceded that it “made no sense economically or geographically,” but the line fell thirty miles north of the Korean capital of Seoul. Though some officers argued that they should move the line further north to the thirty-ninth parallel, the two officers thought they’d be lucky if the Soviets agreed to the thirty-eighth.

The plan was authorized by President Truman on August 14 and telegraphed to the Soviet Union—which, to their surprise, signaled back its agreement on August 16.

Rusk and Bonesteel could not have known that the line would lead to the permanent division of a nation which had been unified for centuries, separating thousands of families and resulting in a war that would claim nearly two million lives.

Korea Colonized

For five centuries, the Joseon dynasty ruled a unified Korean state that paid tribute to neighboring imperial China. The peninsular nation fended off a Japanese invasion in the late sixteenth century with the aid of Chinese troops, as well as a domestically built fleet of armored turtle boats and rocket-propelled arrow artillery. As Western colonial powers expanded into Asia in the nineteenth century, the isolationist “hermit kingdom” violently resisted expeditions by the French Army in 1868 and the U.S. Navy and Marines in 1871.

However, modernizing Meiji Japan had noted the success of Western imperialism in Asia, and decided to emulate its industrialization and expansionism lest Japan fall victim in turn. In 1876, Japanese forces pressured Korea into paying tribute to Tokyo instead of Beijing, opening its ports to Japanese traders and allowing Japanese troops to deploy in the country.

Korean Empress Myeongseong tried to resist by appealing for aid from the faltering Chinese Qing dynasty, but Japan dealt China a humiliating defeat in 1894. She then turned to czarist Russia. But in 1895, the Japanese ambassador dispatched a team of assassins and ronin (masterless samurai) who murdered the queen in her palace and desecrated her body.

In 1910 Japan annexed Korea entirely, effectively making it a colony. The Japanese considered Korea to be backwards, so colonial administration set about industrializing the country and instituting public education. Though Korea experienced rapid economic growth and extensive intermigration during this period, the economy was structured to enrich the colonizer, not the colonized.

Conditions worsened during World War II. Korean-language education was banned and nearly half a million Koreans were drafted for forced labor in Japan. Tens of thousands of Korean women also served as “comfort women,” or sex workers for Japanese troops. While recruits were initially voluntary and paid, increasing demand eventually led to women and girls being tricked or forced to work as sex slaves.